DE102018107153A1 - WIRELESS ENERGY RECEIVING DEVICE AND WIRELESS POWER TRANSMISSION SYSTEM - Google Patents

Abstract

In the present, there is disclosed a wireless power reception apparatus comprising a detection circuit which detects a circuit characteristic of the power reception circuit and a position detection circuit which detects a state of the relative position between the power reception coil and the power transmission coil. The position detection circuit determines that the power receiving coil is present near the periphery of a position suitable for receiving power when the circuit characteristic exceeds a first threshold set between the peak of the second peak and a detection threshold of the detection circuit, and calculates the position detection circuit a transferable energy from the wireless energy transfer device based on the circuit characteristic when the circuit characteristic detected by the detection circuit exceeds a second threshold set between the peak of the second peak and the peak of the first peak.

Description

BACKGROUND OF THE INVENTION

- Field of the invention

The present invention relates to a wireless power reception device and a wireless power transmission system.

- Description of the related art

A wireless power transmission technology is known which employs magnetic coupling between a power transmission (primary) coil and a power receiving (secondary) coil which are opposed to each other to wirelessly transmit AC power applied to the power transmission coil to the power receiving coil.

In performing power transmission by the wireless power transmission technology, it is necessary to achieve alignment between a wireless power transmission device including the power transmission coil and a wireless power receiving device including the power receiving coil. Assuming, for example, that the wireless power transmission device is a charging device buried in the ground and that the wireless power receiving device is disposed on the underside of a vehicle such as an electric car, it is necessary to control the vehicle by manual control of the driver or by to position the automatic control of the system of the vehicle on the loading device.

The use of a mechanical guide can be considered as a concrete method for achieving the positioning. For example, if a guide rail for guiding the wheels of the vehicle is provided, the vehicle can be easily moved to a suitable position. However, the mechanical guidance is not always available, so there is a need to enable positioning even in the absence of mechanical guidance. Under such circumstances, the following system was devised. That is, a magnetic flux generated by the power transmission coil is detected by the wireless power reception device, and the relative positional relationship between the wireless power transmission device and the wireless power reception device is calculated in real time from the detection result to be used in the positioning.

The disclosure of Japanese Patent Application No. 2015 - 116023 discloses an example of such positioning technology. Specifically, a driver performs a parking operation in a state where the output power of a primary coil is set. During the parking operation, if a reception voltage picked up by the wireless power reception apparatus is measured, an image (see FIG. 10A the font) representing that the received voltage of the wireless power receiving device is measured, displayed on a display device such as a car navigation system. Then, at a time when the received voltage of the wireless power receiving device changes from an increase to a decrease, an image (see FIG. 10B the font) representing that the vehicle is in the optimum parking position.

Furthermore, the disclosure of the Japanese Patent Application No. 2015-126658 the relationship between a separation distance between a power transmission coil and a power reception coil in the horizontal direction (hereinafter referred to merely as "horizontal separation distance") and a picked-up voltage picked up by the wireless power reception device in a state where the output power of the power transmission coil is fixed. As in 4 As shown in the figure, the received voltage of the wireless power receiving device has a local minimum value at a position where the horizontal separation distance becomes a predetermined value. The local minimum value occurs due to the reversal of the direction of a magnetic flux linking the power receiving coil.

Again 4 the disclosure of Japanese Patent Application No. 2015-126658 can be seen, the received voltage of the wireless power receiving device in a state in which the output power of the power transmission coil is set, two peaks with different values. One is a larger peak occurring at a position where the horizontal separation distance is substantially "0". The larger tip is hereinafter referred to as "first tip". The other is a smaller peak that occurs at a position from a local peak, as seen from the first peak. The smaller peak will be referred to hereinafter as the "second peak".

Although in the disclosure of Japanese Patent Application No. 2015-116023 Unless stated, in the technique disclosed in the specification, it is likely that a threshold value for the picked-up voltage is set to a value that is greater than the peak value of the second peak, and when the received voltage exceeds the threshold, the image representing that the picked-up voltage of the wireless power receiving device is measured is displayed. This is because if the threshold is set to a value smaller than the peak of the second peak, an image representing that the vehicle is at the optimum parking position is displayed when the picked-up voltage is the second Top tops.

However, in the above-described configuration in which a driver is not notified of a fact that the wireless power receiving device approaches the wireless power transmission device until the received voltage exceeds the threshold value set to a value greater than the peak value of the second peak , the driver does not confirm that the wireless power receiving device is approaching the wireless power transmitting device until the wireless power receiving device approaches the wireless power transmitting device significantly.

OVERVIEW

It is therefore an object of the present invention to provide a wireless power receiving device and a wireless power transmission system capable of notifying a user at a time that the wireless power receiving device is approaching the wireless power transmitting device when the wireless power receiving device is at a power source Position is located, which is located with respect to the wireless power transmission device farther away from the conventional position of the wireless power receiving device.

A wireless power reception apparatus according to the present invention is a device installed in a mobile body and configured to wirelessly receive power transmitted from a wireless power transmission device. The wireless power reception apparatus includes a power receiving circuit including a power receiving coil that accepts alternating current through a magnetic field, and a rectifier circuit that converts the alternating current received from the power receiving coil into direct current and outputs the direct current to a load, a detection circuit having a circuit characteristic of the power receiving circuit with a first A peak having a relatively large peak and a second peak having a relatively small value with respect to a horizontal separation distance between the power transmission coil of the wireless power transmission device and the power receiving coil detects, and a position detecting circuit that detects a state of the relative position between the power receiving coil and the power transmission coil. When the circuit characteristic detected by the detection circuit exceeds a first threshold that is between the peak value of the second peak and a detection threshold of the detection circuit, the position detection circuit determines that the power reception coil is present near the periphery of a position capable of receiving energy from the energy transmission coil receive. When the circuit characteristic detected by the detection circuit exceeds a second threshold set between the peak of the second peak and the peak of the first peak, the position detection circuit calculates an energy transferable from the wireless energy transfer device based on the circuit characteristic detected by the detection circuit ,

According to the present invention, processing for starting an energy transfer (ie, processing for calculating the energy transferable from the wireless energy transfer device based on the circuit characteristic) starts after the circuit characteristic exceeds the second threshold, so that it is in a state where the wireless Power receiving device of the wireless power transmission device, it is possible to notify the user at one time about the approach to the wireless power transmission device when the circuit characteristic exceeds the first threshold (ie, when the wireless power receiving device is located at a position farther away than the wireless energy transmission device conventional notification start position).

In the wireless power reception apparatus, the first threshold may be a detection threshold of the detection circuit. With this configuration, it is possible to expand a margin within which the user can be informed of an approach to the wireless power transmission device to a maximum extent.

In the wireless power reception apparatus, the position detection circuit may change the second threshold according to a vertical distance between the power transmission coil and the power reception coil. Concrete peak values of the respective first and second peaks are reduced as the vertical distance between the power transmission coil and the power receiving coil increases. According to the present embodiment, it is possible to allow the second threshold to conform to one Change the peak of the second peak. As a result, it is possible to expand a range in which transferable energy can be obtained from the wireless power transmission device to a maximum extent.

In the wireless power reception apparatus, the position detection circuit may determine that alignment between the power transmission coil and the power receiving coil is not properly performed when the circuit characteristic detected by the detection circuit does not exceed the second threshold within a certain period from when it exceeds the first threshold. This allows a user to perceive that alignment between the power transmission coil and the power receiving coil fails.

In the wireless power reception apparatus, the position detection circuit may determine that alignment between the power transmission coil and the power reception coil is not properly performed when the circuit characteristic detected by the detection circuit does not exceed the second threshold during a period from when it exceeds the first threshold when the mobile body is moved a predetermined distance. This allows a user, as it were, to perceive that alignment between the power transmission coil and the power reception coil fails.

The wireless power receiving device may further include a power receiving alarm informing a user or an external device of information. The power reception side alarm may notify the user or the external device of a detection result of the position detection circuit and the transmittable energy calculated by the position detection circuit. This allows the user or the external device to guide the mobile body to a position where the power transmitting device and the power receiving device face each other directly.

In the wireless power reception apparatus, the power receiving circuit may further include a switching circuit that switches a connection state between the output end of the rectifier circuit and the load. The circuit may open the output end of the rectifier circuit during processing by the position detection circuit. This can make the circuit characteristic of the power receiving circuit independent of the load, so that the position detecting circuit can make a comparison between the first and second threshold and the circuit characteristic and the computation of the transmittable power with higher accuracy.

In the wireless power reception apparatus, the power receiving circuit may further include a load resistor having a fixed resistance and a switching circuit that switches a connection state between the output end of the rectifier circuit and the load or the load resistor. During processing by the position detection circuit, the circuit may connect the output end of the rectifier circuit to the load resistor. This can also make the circuit characteristic of the power receiving circuit independent of the load, so that the position detecting circuit can make a comparison between the first and second threshold and the circuit characteristic and the calculation of the transmittable energy with higher accuracy.

A wireless power transmission system according to the present invention is a system that wirelessly transmits power from a wireless power transmission device to a wireless power receiving device, wherein the wireless power transmission device converts a power conversion circuit that converts input DC power into AC power, a power transmission coil that receives the AC power supplied by the power conversion circuit to generate an AC magnetic field, and includes a control circuit that controls the AC power to be supplied to the power transmission coil, and the wireless power receiving device is one of the above wireless power receiving devices.

In the wireless power transmission system, the control circuit to control the AC power to be supplied to the power transmission coil so that the amount of magnetic flux generated by the power transmission coil is constantly controlled. Thus, processing of the position detection circuit can be suitably performed.

A wireless power transmission system according to another aspect of the present invention is a system that wirelessly transmits power from a wireless power transmission device to a wireless power receiving device, the wireless power transmission device including a power converter circuit that converts input DC power to AC power, an energy transmission coil that is the one from the power converter circuit supplied AC power to generate an AC magnetic field, and comprises a control circuit which controls the to be supplied to the power transmission coil AC, and wherein the wireless power receiving device comprises a power receiving circuit, which receives a power receiving coil, the AC by the AC magnetic field, and a rectifier circuit, the converts the AC power consumed by the power receiving coil into DC power and outputs the DC power to a load and a detection circuit that detects a circuit characteristic of the power receiving coil having a first peak having a relatively large peak and a small peak having a relatively small (peak) value with respect to a horizontal separation distance between the power transmission coil of the wireless power transmission device and the power receiving coil. When the circuit characteristic detected by the detection circuit exceeds a first threshold set between the peak value of the second peak and a detection threshold of the detection circuit, the control circuit determines that the power reception coil is present near the periphery of a position suitable for receiving energy from the energy transmission coil. When the circuit characteristic detected by the detection circuit exceeds a second threshold set between the peak of the second peak and the peak of the first peak, the control circuit calculates an energy transferable from the wireless power transmission device to the wireless power reception device based on the detection circuit detected circuit characteristic.

According to the present invention, in a state in which the wireless power receiving device approaches the wireless power transmission device, a user may be notified of approaching the wireless power transmission device at a time when the circuit characteristic exceeds the first threshold (ie, when the wireless power receiving device a position that is farther away from the wireless power transmission device than the conventional notification start position).

list of figures

• 1 eine Ansicht ist, die einen Nutzungszustand eines drahtlosen Energieübertragungssystems gemäß einer ersten Erfindung veranschaulicht;
• 2 eine Ansicht ist, die schematisch eine Bewegung des Fahrzeugs Ve darstellt, wenn das in 1 dargestellte Laden des Fahrzeugs Ve durchgeführt wird;
• 3 eine Ansicht ist, die die Beziehung zwischen dem horizontalen Trennungsabstand D und einer aufgenommenen Spannung darstellt, die in der drahtlosen Energieempfangsvorrichtung Ur erzeugt wird, wenn ein von der Energieübertragungsspule erzeugter magnetischer Fluss die Energieempfangsspule verknüpft;
• 4 eine Ansicht ist, die die Konfiguration eines drahtlosen Energieübertragungssystems S gemäß der ersten Ausführungsform der vorliegenden Erfindung darstellt;
• 5 ein Ablaufdiagramm ist, das einen Verarbeitungsablauf der in 4 gezeigten Positionserfassungsschaltung Dru2 darstellt;
• 6 ein Ablaufdiagramm ist, das einen Verarbeitungsablauf der in 4 gezeigten Steuerschaltung Stu darstellt;
• 7 eine Ansicht ist, die die Konfiguration eines drahtlosen Energieübertragungssystems S gemäß einer zweiten Ausführungsform der vorliegenden Erfindung darstellt;
• 8 eine Ansicht ist, die die Konfiguration eines drahtlosen Energieübertragungssystems S gemäß einer dritten Ausführungsform der vorliegenden Erfindung darstellt; und
• 9 eine Ansicht ist, die die Konfiguration eines drahtlosen Energieübertragungssystems S gemäß einer vierten Ausführungsform der vorliegenden Erfindung darstellt.

The above and other objects, features and advantages of this invention will become more apparent by reference to the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which:

• 1 Fig. 13 is a view illustrating a usage state of a wireless power transmission system according to a first invention;
• 2 is a view schematically illustrating a movement of the vehicle Ve when the in 1 shown charging the vehicle Ve is performed;
• 3 Fig. 12 is a view illustrating the relationship between the horizontal separation distance D and a picked-up voltage generated in the wireless power receiving device Ur when a magnetic flux generated by the power transmission coil couples the power receiving coil;
• 4 is a view illustrating the configuration of a wireless power transmission system S according to the first embodiment of the present invention;
• 5 FIG. 10 is a flowchart illustrating a processing flow of the in 4 shown position detection circuit Dru2 represents;
• 6 FIG. 10 is a flowchart illustrating a processing flow of the in 4 shown control circuit Stu represents;
• 7 is a view illustrating the configuration of a wireless power transmission system S according to a second embodiment of the present invention;
• 8th is a view illustrating the configuration of a wireless power transmission system S according to a third embodiment of the present invention; and
• 9 is a view illustrating the configuration of a wireless power transmission system S according to a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be explained in detail with reference to the drawings.

1 FIG. 13 is a view illustrating a usage state of a wireless power transmission system according to an embodiment of the present invention. FIG. As illustrated, the wireless power transmission system according to the embodiment is composed of a wireless power transmission device Ut including a power transmission coil unit Ltu and a wireless power reception device Ur including a power reception coil unit Lru. The power transmission coil unit Ltu is a device installed on a road surface and includes a power transmission coil (not shown). The power reception coil unit Lru is a device installed on the underside of a vehicle Ve and includes a Energy receiving coil (not shown). The vehicle Ve is, for example, an electric car.

In performing the charging of the vehicle Ve, a user moves the vehicle Ve to a location above the power transmission coil unit Ltu to arrange the power reception coil unit Lru in a magnetic field generated by the transmission coil. As a result, power is transmitted to the wireless power receiving device Ur by magnetic coupling between the power transmission coil and the power receiving coil from the wireless power transmitting device Ut, and a secondary battery (not shown) in the vehicle Ve is charged by the thus transmitted power.

The relative positional relationship between the power transmission coil and the power receiving coil is represented by a vertical separation distance Z and a horizontal separation distance D, which in FIG 1 are illustrated. The vertical separation distance Z is generally determined by the height of the floor surface of the vehicle Ve. That is, the higher the height of the floor surface of the vehicle Ve, the larger the distance between the energy receiving coil and the road surface, that is, the larger becomes the vertical separation distance Z. On the other hand, the horizontal separation distance D becomes smaller as the vehicle is closer to Power transmission coil unit Ltu comes, and becomes larger as the vehicle Ve moves away from the power transmission coil unit Ltu.

2 FIG. 15 is a view schematically illustrating a movement of the vehicle Ve when the loading of the vehicle Ve is performed. As illustrated, a user (driver) of the vehicle Ve moves the vehicle Ve along the arrow A1 such that the vehicle Ve is positioned just above the energy transmission coil unit Ltu. At this time, the in 1 The separation distance D shown when the vehicle Ve approaches the energy transmission coil unit Ltu and becomes "0" in a state where the vehicle Ve is positioned just above the energy transmission coil unit Ltu. The in 2 indicated arrow A2 indicates an example of misalignment, the details of which will be described later.

3 FIG. 12 is a graph showing the relationship between the horizontal separation distance D and a picked-up voltage (specifically, the output voltage of a rectifier circuit DB 4 ) generated in the wireless power receiving device Ur when a magnetic flux generated by the power transmission coil couples the power receiving coil. The data of the graph 3 are obtained when the power of the power transmission coil is fixed.

As in 3 As shown, the received voltage has two peaks of different values in a state where the power of the power transmission coil is fixed. A larger peak P1 (first peak) occurs at a position where the horizontal separation distance D is substantially "0". A smaller peak P2 (second peak) occurs at a position opposite to a local minimum value M when viewed from the tip P1. The peak value of each of the peaks P1 and P2 increases as the vertical separation distance Z decreases.

The value M of the local minimum occurs at a position where the direction of a magnetic flux connecting the power receiving coil is reversed. As in 3 That is, the value of the horizontal separation distance D corresponding to the position where the local min value M occurs remains almost the same even if the vertical separation distance Z changes.

Although the details will be described later, the wireless power receiving device Ur uses the in 3 shown thresholds T1 and T2 to perform a processing according to the present invention. The threshold T1 (first threshold) is set between the peak value of the peak P2 and a detection threshold (lower limit in the present embodiment) of a detection circuit Dru1. The threshold T2 (second threshold) is set between the peak value of the peak P2 and the peak value of the peak P1.

In the present embodiment, the peaks P1 and P2 each take a value of a local maximum, so that the threshold values T1 and T2 thus set are a value smaller than the peak value of the peak P2 and a value larger than the peak value of the peak P2 is, but is smaller than the peak of the peak P1. However, the peaks P1 and P2 may each take on a local minimum value which depends on the kind of circuit characteristic to be described later. In such a case, the threshold values T1 and T2 are a value larger than the peak value of the peak P2 and a value smaller than the peak value of the peak P2 but larger than the peak value of the peak P1.

With reference to 2 are positions where the received voltage takes the value M of the local minimum, and thresholds T1 and T2 are concentrically arranged around the power transmission coil unit Ltu. The radii of concentric circles take in the order of Threshold T1, the local minimum M and the threshold T2. Thus, the value of the absorbed voltage is inevitably changed in the order of the threshold value T1, the local minimum M, and the threshold value T2 when the vehicle Ve approaches the power transmission coil unit Ltu. The wireless power receiving device Ur according to the present embodiment utilizes such a built-in voltage characteristic to enable a user to be notified of the approach of the wireless power receiving device Ur to the wireless power transmitting device Ut at a time when the wireless power receiving device Ur is in a position which is farther away from the wireless power transmission device Ut than the conventional position of the wireless power reception device. Hereinafter, the configuration of the wireless power receiving device Ur will be described in detail.

4 FIG. 14 is a view illustrating the configuration of a wireless power transmission system S according to the present embodiment. As shown, the wireless power transmission system S according to the present embodiment includes the wireless power transmission device Ut and the wireless power reception device Ur.

The wireless power receiving device Ur is a device mounted on a mobile body, and is configured to receive power wirelessly transmitted from the wireless power transmission device Ut. The wireless power receiving device Ur includes, in addition to the power receiving coil unit Lru included in FIG 1 a rectifier circuit DB, a detection circuit Dru1, a position detection circuit Dru2, an alarm Au, and a wireless communication module Wru. The power receiving coil unit Lru and the rectifier circuit DB constitute a power receiving circuit Cr of the wireless power receiving device Ur.

The power reception coil unit Lru includes a power receiving coil which receives AC power through a magnetic field generated by the power transmission coil unit Ltu. The rectifier circuit DB is a circuit that converts power absorbed by the power receiving coil into DC power. The DC current generated by the rectifier circuit DB is supplied to a load L. The load L is, for example, a secondary battery included in the in 1 illustrated vehicle Ve is provided.

The detection circuit Dru1 is a circuit that detects a circuit characteristic of the power reception circuit Cr. The circuit characteristic may be a value with the above-mentioned peaks P1 and P2 with respect to the horizontal separation distance D, and is typically the output voltage (received voltage) of the rectifier circuit DB.

The alarm Au (power reception-side alarm) is a device that notifies a user or an external device (not shown) about information. Information indicated by the alarm Au includes a determination result (to be described later) of the position detecting circuit Dru2 and a transmittable power (to be described later) calculated by the position detecting circuit Dru2. A concrete notification method will be described later. A user moves the vehicle Ve such that the power transmission coil and the power receiving coil are aligned based on the thus notified information. The external device is a device that manages an automatic operation function of the vehicle Ve. Like the manual operation of the user, the external device moves the vehicle Ve such that the power transmission coil and the power receiving coil are aligned based on the information thus communicated.

The wireless communication module Wru is a module having a wireless communication function, and is configured to perform wireless communication with a wireless communication module Wtu (to be described later) in the wireless power transmission device Ut. Between the above modules, schemes of near-field wireless communications such as WLAN or Bluetooth® may be suitably used. The role of the wireless communication module Wru will be described later, along with an explanation of the configuration of the wireless power transmission device Ut.

The position detecting circuit Dru2 is a circuit for detecting a state of the relative position between the power receiving coil and the power transmitting coil. Specifically, the position detecting circuit Dru2 is configured to set a state of the relative position between the power receiving coil and the power transmission coil using the in 3 detected thresholds T1 and T2. Next, a processing performed by the position detecting circuit Dru2 will be described. While the position detection circuit Dru2 performs the subsequent processing, the wireless power transmission device Ut controls the amount of magnetic flux generated by the power transmission coil to a constant value. Details of the wireless power transmission device Ut performed scheme will be described later.

When the characteristic detected by the detection circuit Dru1 exceeds the threshold value T1, the position detection circuit Dru2 determines that the power reception coil is present near the periphery of a position suitable for receiving energy from the energy transmission coil. Then, the position detection circuit Dru2 uses the alarm Au to notify the user or the external device of the determination result. Specifically, the position detecting circuit Dru2 performs a first display (for example, lighting up) corresponding to a determination result indicating that the power receiving coil is located near the periphery of a position suitable for receiving energy from the power transmitting coil; while performing a second display (for example, extinction) that corresponds to a determination result indicating that the power reception coil is not present near the periphery of a position suitable for receiving energy from the power transmission coil.

Like the threshold T1, a lower detection threshold for the detection circuit Dru1 (the minimum circuit characteristic that the detection circuit Dru1 can detect) may be used. In this case, when the circuit characteristic is detected by the detection circuit Dru1, the position detection circuit Dru2 determines that the power reception coil is present near the periphery of a position suitable for receiving energy from the power transmission coil.

When the circuit characteristic detected by the detection circuit Dru1 exceeds the threshold T2, the position detection circuit Dru2 calculates an energy transferable from the wireless power transmission device Ut based on the circuit characteristic detected by the detection circuit Dru1. The position detection circuit Dru2 then uses the alarm Au to notify the user or the external device of the calculated, transferable energy. Specifically, the position detecting circuit Dru2 preferably performs the notification by displaying a bar graph.

The position detecting circuit Dru2 further performs processing of determining that alignment between the power transmitting coil and the power receiving coil is not properly performed when the circuit characteristic detected by the detecting circuit Dru1 does not exceed the threshold T2 within a period of time from the threshold value T1 being exceeded. Alternatively, in a case where vehicle speed information based on vehicle speed pulses or position information based on GPS satellites can be obtained, it can be determined that alignment between the power transmission coil and the power receiving coil is not properly performed when the circuit characteristic output from the detection circuit Dru1 which does not exceed the threshold value T2 during a period from when it exceeds the threshold value T1 until when the vehicle Ve has been moved by a predetermined distance.

A case in which the circuit characteristic does not exceed the threshold value T2 may occur, for example, when the vehicle Ve is traveling along the in-line 2 shown arrow A2 is moved. That is, when the vehicle Ve is moved along the arrow A2, the circuit characteristic value never exceeds the threshold T2 even after the threshold T1 has been exceeded. In such a case, the position detection circuit Dru2 determines that alignment between the power transmission coil and the power reception coil has not been performed properly.

If it is determined that alignment between the power transmission coil and the power reception coil has not been properly performed, the position detection circuit Dru2 may notify the user or the external device of the error or failure by means of the alarm Au. This allows a user or an external device to perceive that alignment between the power transmission coil and the power receiving coil has not been properly performed, and if necessary, to subsequently perform appropriate processing, such as retrying to align from the beginning.

5 Fig. 10 is a flowchart illustrating a processing of the position detecting circuit Dru2. Hereinafter, the processing performed by the position detecting circuit Dru2 will be explained in more detail with reference to FIG 5 carried out.

As in 5 That is, the position detecting circuit Dru2 obtains the circuit characteristic of the power receiving circuit Cr from the detecting circuit Dru1 (step S1), and determines whether or not the obtained circuit characteristic value exceeds the threshold value T1 (step S2). If it is determined that the circuit characteristic does not exceed the threshold value T1, the position detection circuit Dru2 returns to step S1 and obtains the circuit characteristic again. If on the other hand, when it is determined that the circuit characteristic value exceeds the threshold value T1, the position detecting circuit Dru2 replaces the current time with a variable T0 (step S3), and uses the alarm Au to notify that the circuit characteristic value exceeds the threshold value T1 (step S4). ,

Subsequently, the position detecting circuit Dru2 acquires the circuit characteristic of the power receiving circuit Cr a second time from the detecting circuit Dru1 (step S5), and then determines whether or not the obtained circuit characteristic value exceeds the threshold value T2 (step S6). If it is determined that the obtained circuit characteristic does not exceed the threshold value T2, the position detection circuit Dru2 determines whether the alignment between the power transmission coil and the power receiving coil fails (is not performed properly) or not (step S7). Specifically, in 5 determines whether or not a difference between the current time and the variable T0 exceeds a predetermined value. That is, it is determined whether or not a predetermined time has elapsed since the circuit characteristic exceeded the threshold value T1; alternatively, as described above, it may be determined whether the vehicle Ve has been moved a predetermined distance since the circuit characteristic value has exceeded the threshold value T1.

If it is determined in step S7 that an alignment between the power transmission coil and the power reception coil fails (when a difference between the current time and a variable T0 exceeds a predetermined value), the position detection circuit Dru2 uses the alarm Au to notify that the alignment between the power transmission coil and the power receiving coil fails (step S8). Then, the position detection circuit Dru2 returns to step S1 and acquires the circuit characteristic again. The processing flow may return to step S1 immediately after the affirmative determination (YES) in step S7, skipping the processing of step S8. This corresponds to a simple reset of the position detection circuit Dru2. On the other hand, if it is determined in step S7 that an alignment between the power transmission coil and the power receiving coil does not fail (if a difference between the current time and the variable T0 does not exceed a predetermined value), the position detecting circuit Dru2 returns to step S4 and acquires the circuit characteristic again.

If it is determined in step S5 that the circuit characteristic value exceeds the threshold value T2, the position detection circuit Dru2 calculates a transmittable energy based on the most recent circuit characteristic value obtained in step S5 (step S9). Specifically, a transmittable energy corresponding to the most recent circuit characteristic obtained in step S5 may be read out from a pre-prepared look-up table between the circuit characteristic and the transmittable energy. Then, the position detecting circuit Dru2 uses the alarm Au to make a notification of the calculated transferable energy.

As described above with the wireless power receiving device Ur in the present embodiment, the processing for starting the power transmission (i.e., the processing for calculating the power transferable from the wireless power transmission device Ut based on the circuit characteristic) starts after the circuit characteristic value exceeds the threshold value T2. Thus, in a state where the wireless power receiving device Ur approaches the wireless power transmission device Ut, it is possible to notify the user of approaching the wireless power transmission device Ut at a time when the circuit characteristic value exceeds the threshold value T1 (ie wireless power reception device Ur is located at a position farther away than the conventional notification start position of the wireless power reception device Ur with respect to the wireless power transmission device Ut).

Further, it is possible to expand an area where an approach to the wireless power transmission device Ut can be notified to a user to a maximum extent when the threshold value T1 is set to the detection lower limit value for the detection circuit Dru1.

Further, it may be determined that alignment between the power transmission coil and the power reception coil has not been properly performed when the circuit characteristic detected by the detection circuit Dru1 does not exceed the threshold value T2 within a period from when it exceeds the threshold value T1 (or during a period from when it exceeds the threshold T1 until when the vehicle Ve is moved a predetermined distance). Thus, a user may perceive that alignment between the power transmission coil and the power receiving coil fails.

Further, the determination result (specifically, whether the circuit characteristic is the threshold T1 exceeds or not) of the position detecting circuit Dru2 and the transmittable energy calculated by the position detecting circuit Dru2 are notified to a user or the external device by means of the alarm Au, allowing the user or the external device to route the vehicle Ve to a position the energy transmission coil and the energy receiving coil face each other directly.

With reference to 4 the configuration of the wireless power transmission device Ut will be described. The wireless power transmission device Ut comprises, in addition to that also in FIG 1 shown power transmission coil unit Ltu, a power supply circuit PC, a power converter circuit PS, a control circuit Stu, a current detection circuit Dtu and a wireless communication module Wtu. The power supply circuit PC, the power converter circuit PS, and the power transmission coil unit Ltu constitute a power transmission circuit Ct of the wireless power transmission device Ut.

The power supply circuit PC is a circuit that converts an AC power supplied from an external power supply PW, which is, for example, a commercial AC power supply, into desired DC power and outputs the DC power, and is driven by, for example, a PFC (Power Factor Correction). Circuit or a stabilizing power supply formed.

The power converter circuit PS is a circuit that converts the DC power supplied from the power supply circuit PC into AC of a predetermined drive frequency, and is concretely a switching power supply that includes a plurality of switching elements. The switching elements are connected to each other bridge. Examples of the switching element include a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and an IGBT (Insulated Gate Bipolar Transistor).

The power transmission coil unit Ltu includes the power transmission coil that receives AC power from the power conversion circuit PS to generate an AC magnetic field. When the AC power generated by the power conversion circuit PS is supplied to both ends of the power transmission coil, an AC current flows in the power transmission coil, thereby generating the AC magnetic field around the power transmission coil. When the power receiving coil enters the AC magnetic field, an induced current flows in the power receiving coil. Thus, power transmission from the wireless power transmission device Ut to the wireless power reception device Ur is realized. The power transmission coil unit Ltu may include a capacitor connected to the power transmission coil and forming a resonance circuit together with the power transmission coil.

The current detection circuit Dtu is a circuit that detects a value (hereinafter referred to as "current value of the power transmission coil") of current flowing in the power transmission coil included in the power transmission coil unit Ltu. The current detection circuit Dtu outputs the detected current value of the power transmission coil to the control circuit Stu.

The wireless communication module Wtu is a module having a wireless communication function and configured to perform wireless communication with the wireless communication module Wru in the wireless power reception device Ur. The position detecting circuit Dru2 of the wireless power receiving device Ur is configured to transmit by the wireless communication the circuit characteristic (eg, the output voltage of the rectifier circuit DB) detected by the detecting circuit Dru1 in response to a request made by the control circuit Stu through the wireless communication was transferred.

The control circuit Stu is a circuit that calculates a relative position ratio (specifically, the above-mentioned separation distances Z and D) between the power transmission coil and the power receiving coil, calculates a transmittable energy from the calculated relative position ratio, and the operation of the power transmission circuit Ct based on the calculated transmittable power Energy controls. The control circuit Stu further transmits the calculated vertical separation distance Z to the wireless power receiving device Ur. Hereinafter, with reference to the flowchart 6 the function of the control circuit Stu described in detail.

6 Fig. 10 is a flowchart illustrating a processing procedure of the control circuit Stu. The control circuit Stu controls the circuit characteristic of the wireless power transmission device Ut to keep the amount of magnetic flux generated by the power transmission coil constant (step S20). The processing of the position detecting circuit Dru2 described in the first embodiment is performed in a state where the amount of magnetic flux generated by the energy transmitting coil is thus controlled to a constant value. Examples of the circuit characteristic include various values, such as a DC output current Power supply circuit PC, DC, which is supplied from the power supply circuit PC of the power converter circuit PS, a frequency of AC power generated by the power converter circuit PS, and a time ratio (ON / OFF operation) of the plurality of switching elements which form the power converter circuit PS.

In the case where the output DC current of the power supply circuit PC, the DC output voltage of the power supply circuit PC or a DC power supplied from the power supply circuit PC to the power converter circuit PS is used as the circuit characteristic of the wireless power transmission device Ut, the control circuit Stu controls the power supply circuit PC to thereby control the power supply circuit PC Circuit characteristic of the wireless power transmission device to control Ut. On the other hand, the control circuit Stu controls the power converter circuit PS to thereby control the circuit characteristic of the wireless power transmission device Ut, if the frequency (the above-mentioned drive frequency) of AC generated by the power converter circuit PS or the time ratio (ON / OFF operation) of the plurality of switching elements , which constitute the power converter circuit PS, are used as the circuit characteristic of the wireless power transmission apparatus Ut.

Further, the control circuit Stu uses the above-mentioned current value of the power transmission coil as a monitor value for detecting whether or not the amount of magnetic flux generated by the power transmission coil in the power transmission coil unit Ltu is constant. That is, the control circuit Stu controls the circuit characteristic of the wireless power transmission device Ut to keep the current value of the power transmission coil constant, thereby to constantly control the amount of magnetic flux generated by the power transmission coil. Thus, it can be said that the amount of magnetic flux generated by the energy transfer coil is constant when the current value of the energy transfer coil is constant, so that it is possible to control the amount of magnetic flux generated by the energy transfer coil through this control. Although the current value of the power transmission coil detected by the power detection circuit Dtu is used to detect whether or not the amount of magnetic flux generated by the power transmission coil in the power transmission coil unit Ltu is constant in the present embodiment, other methods may be used capable of detecting whether or not the amount of magnetic flux generated by the power transmission coil is constant.

Then, the control circuit Stu obtains the circuit characteristic of the wireless power transmission device Ut in a state where the amount of magnetic flux generated by the power transmission coil is constant (step S21). The circuit characteristic value obtained thereby is the same as the circuit characteristic value to be controlled in step S2. Then, the control circuit Stu calculates the vertical separation distance Z from the obtained circuit characteristic (step S22). The inductance value of the energy transfer coil varies depending on the vertical separation distance Z, and the change in the inductance value of the energy transfer coil is reflected in the circuit characteristic required to control the amount of magnetic flux generated by the energy transfer coil to a constant value, so that the control circuit Stu can calculate the vertical separation distance Z on the basis of the circuit characteristic obtained in step S21. Concretely, a vertical separation distance Z corresponding to the obtained circuit characteristic value is read out from a pre-prepared look-up table between the circuit characteristic value and the vertical separation distance Z.

Concretely, the control circuit Stu uses the wireless communication module Wtu to transmit the calculated vertical separation distance Z to the wireless power receiving device Ur (step S23). The processing performed by the wireless power receiving device Ur after receiving the calculated vertical separation distance Z will be described later.

Then, the control circuit Stu uses the wireless communication module Wtu to receive the circuit characteristic (eg, the output voltage of the rectifier circuit DB) from the wireless power receiving device Ur (step S24), and then calculates the coupling coefficient between the power transmission coil and the power receiving coil from the received circuit characteristic (Step S25).

Then, the control circuit Stu calculates the horizontal separation distance D based on the vertical separation distance Z calculated in step S22 and the coupling coefficient calculated in step S25 (step S26). The coupling coefficient changes based on the horizontal separation distance D if the vertical separation distance Z is not changed, so that the control circuit Stu can calculate the horizontal separation distance D based on the vertical separation distance Z and the coupling coefficient. Specifically, the look-up tables between the coupling coefficient and the vertical separation distance D become previously prepared for each vertical separation distance Z, and a look-up table corresponding to the vertical separation distance Z calculated in step S22 is read out. Then, from this look-up table, the horizontal separation distance D corresponding to the coupling coefficient calculated in step S25 is read out.

Then, the control circuit Stu calculates the transmittable energy from the calculated separation distances Z and D (step S27). Concretely, a transferable energy is read out from a pre-established look-up table between the separation distances Z and D and the transmittable energy corresponding to the calculated separation distances Z and D.

Finally, the control circuit Stu controls the operation of the power transmission circuit Ct based on the calculated, transferable energy (step S28). For example, the control circuit Stu controls the operation of one of the power supply circuit PC and the power converter circuit PS to realize transmission of the energy calculated in step S27. Thus, the power transmission to the wireless power receiving device Ur is performed with a power suitable for the relative positional relationship between the power transmitting coil and the power receiving coil.

With reference to 4 For example, the position detecting circuit Dru2 of the wireless power receiving device Ur is configured to receive the vertical separation distance Z transmitted in step S23. The position detecting circuit Dru2 changes the threshold T2 in accordance with the received calculated vertical separation distance Z. Specifically, the position detecting circuit Dru2 decreases the threshold value T2 as the vertical separation distance Z becomes larger. This processing corresponds to a fact that the larger the vertical separation distance Z is, the smaller the received voltage becomes, as in FIG 3 is shown. This allows the threshold T2 to adjust to a change in the peak value of the peak P2 according to the vertical separation distance Z.

As described above, in the wireless power transmission system S in the present embodiment, the amount of magnetic flux generated by the power transmission coil can be controlled to be constant. Thus, the in 3 to allow the processing of the position detecting circuit Dru2 to be performed suitably.

Further, the threshold value T2 may be changed according to the calculated vertical separation distance Z, allowing the threshold value T2 to be adapted to a change in the peak value of the peak P2 according to the vertical separation distance Z.

7 FIG. 14 is a view illustrating the configuration of a wireless power transmission system S according to a second embodiment of the present invention. The wireless power transmission system S of the present embodiment differs from the wireless power transmission system S according to the first embodiment in that the wireless power receiving device Ur has a switching circuit SW1 in the power receiving circuit Cr. The same parts as those in the first embodiment will be denoted by the same reference numerals, and points different from those of the first embodiment will be mainly described.

The circuit SW1 is a circuit for switching a connection state between the output end of the rectifier circuit DB and the load L. Concretely, the circuit SW1 is arranged between a state in which the output end of the rectifier circuit DB is connected to the load L and a state wherein the output end of the rectifier circuit DB is open to switch.

The position detecting circuit Dru2 according to the present embodiment controls the switching circuit SW1 to the output end of the rectifier circuit DB during processing 5 to open. Otherwise, the output end of the rectifier circuit DB is connected to the load L. This can make the circuit characteristic (the value detected by the detection circuit Dru1) of the power receiving circuit Cr independent of the load L, so that the position detecting circuit Dru2 can make a comparison between the thresholds T1, T2 and the circuit characteristic and calculating the transmittable power with higher accuracy can perform.

8th FIG. 14 is a view illustrating the configuration of a wireless power transmission system S according to a third embodiment of the present invention. The wireless power transmission system S of the present embodiment differs from the wireless power transmission system S according to the second embodiment in that it has a switching circuit SW2 instead of the switching circuit SW1. The same parts as those in the second embodiment will be denoted by the same reference numerals and points mainly different from those of the second embodiment will be described.

The switching circuit SW2 is arranged to switch a connection state between the output end of the rectifier circuit DB and the load L, and is therefore the same as the circuit SW1, but differs therefrom in that the output end of the rectifier circuit DB is in a state in which it is not is connected to the load L, is connected to a load resistor R having a predetermined resistance value.

The position detecting circuit Dru2 according to the present embodiment controls the switching circuit SW2 to be during processing 5 connect the output end of the rectifier circuit DB to the load resistor R. Otherwise, the output end of the rectifier circuit DB is connected to the load L. This can make the circuit characteristic (the value detected by the detecting circuit Dru1) of the power receiving circuit Cr independent of the load L as in the second embodiment, so that the position detecting circuit Dru2 compares between the thresholds T1, T2 and the circuit characteristic and the transferable energy calculation can perform with higher accuracy than in the second embodiment.

9 FIG. 14 is a view illustrating the configuration of a wireless power transmission system S according to a fourth embodiment of the present invention. The wireless power transmission system S of the present embodiment differs from the wireless power transmission system S according to the first embodiment in that the control circuit Stu in the wireless power transmission device Ut has a function corresponding to the position detection circuit Dru2 and in that the position detection circuit Dru2 is not in the wireless Power receiving device Ur is provided. The same parts as those in the first embodiment will be denoted by the same reference numerals, and points other than those of the first embodiment will be mainly described.

The detection circuit Dru1 according to the present embodiment is arranged to perform a function of wirelessly transmitting the circuit characteristic (eg, the output voltage of the rectifier circuit DB) of the power reception circuit Cr in response to a request from the control circuit Stu, in the context of the functions of the position detection circuit Dru2 described in the first embodiment of the position detecting circuit Dru2.

The control circuit Stu according to the present embodiment performs the same processing as that performed by the position detection circuit Dru2 in the first embodiment based on the circuit characteristic value received from the detection circuit Dru1. Concretely, the control circuit Stu determines that the power reception coil is near the periphery of a position suitable for receiving energy from the power transmission coil when the circuit characteristic detected by the detection circuit Dru1 exceeds the threshold value T1. Then, when the characteristic detected by the detection circuit Dru1 exceeds the threshold value T2, the control circuit Stu calculates the energy transferable to the wireless power reception device Ur based on the circuit characteristic detected by the detection circuit Dru1. The processing to be performed by the control circuit Stu is as described above, so that descriptions thereof are omitted. The content of the notification by the alarm Au is also as described above in the first embodiment, and the control circuit Stu controls the alarm Au through the wireless communication modules Wtu and Wru.

As described above, the processing performed by the wireless power transmission device Ut in the wireless power transmission system S in the present embodiment enables an approach to the wireless power transmission device Ut to be notified to a user at a time when the circuit characteristic value exceeds the threshold value T1 (that is, if the wireless power receiving device Ur regarding the wireless power transmission device Ut is located at a position farther than the conventional notification start position) in a state where the wireless power receiving device Ur approaches the wireless power transmission device Ut.

It will be understood that the present invention is not limited to the above embodiments, but may be changed and modified without departing from the scope and spirit of the invention.

For example, in the above embodiments, the vehicle Ve is illustrated as an energy transmission target; However, the present invention can be suitably applied to a case where mobile bodies other than the vehicle Ve are given as the power transmission target. For example, the present invention can be conveniently applied to a case in which a mobile device such as a tablet terminal or a smartphone are specified as the energy transfer destination.

Further, in the above embodiments, the vertical separation distance Z is transmitted from the wireless power transmission device Ut to the wireless power receiving device Ur; however, if the height of the floor surface of the vehicle Ve is known in advance, the wireless power receiving device Ur may relate the vertical separation distance Z from the height of the floor surface of the vehicle Ve. In this case, the position detection circuit Dru2 described in the first to third embodiments may change the threshold value T2 according to the vertical separation distance Z without needing to receive the vertical separation distance Z from the wireless power transmission device Ut. The height of the floor surface of the vehicle Ve generally does not vary, so that the processing of a change of the threshold value T2 can be performed only once in response to obtaining the vertical separation distance Z by the wireless power receiving device Ur.

Further, in the above embodiments, the alarm Au is provided only in the wireless power receiving device Ur; however, an alarm may also be provided in the wireless power transmission device Ut and arranged to perform a notification operation at the same time as the alarm Au in the wireless power receiving device Ur. In this case, the position detection circuit Dru2 can control the alarm in the wireless power transmission device Ut by wireless communication between the wireless communication modules Wtu and Wru included in the wireless communication modules 8th are illustrated.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2015 [0005]
• JP 116023 [0005]
• JP 2015126658 [0006, 0007]
• JP 2015116023 [0008]

Claims (11)

A wireless power reception device mounted in a mobile body and configured to wirelessly receive power transmitted by a wireless power transmission device, the wireless power reception device comprising: a power receiving circuit including a power receiving coil that accepts AC power through a magnetic field, and a rectifier circuit that converts the AC power received from the power receiving coil into DC power and outputs the DC power to a load; a detection circuit that detects a circuit characteristic of the power receiving circuit having a first peak having a relatively large peak and a second peak having a relatively small value with respect to a horizontal separation distance between a power transmission coil of the wireless power transmission device and the power receiving coil; and a position detecting circuit that detects a state of the relative position between the power receiving coil and the power transmitting coil, the position detecting circuit determining that the power receiving coil is located near the periphery of a position capable of receiving power from the power transmitting coil when the circuit characteristic detected by the detecting circuit exceeds a first threshold value that lies between the peak value of the second peak and a detection threshold of the detection circuit, and the position detection circuit calculates an energy transmittable by the wireless energy transmission device based on the circuit characteristic value detected by the detection circuit when the circuit characteristic value detected by the detection circuit has exceeds the second threshold set between the peak of the second peak and the peak of the first peak. Wireless energy receiving device after Claim 1 wherein the first threshold is a detection threshold of the detection circuit. Wireless energy receiving device after Claim 1 or 2 wherein the position detecting circuit changes the second threshold according to a vertical distance between the power transmitting coil and the power receiving coil. Wireless energy receiving device according to one of Claims 1 to 3 wherein the position detection circuit determines that alignment between the power transmission coil and the power receiving coil is not properly performed when the circuit characteristic detected by the detection circuit does not exceed the second threshold within a predetermined time period from when the circuit characteristic value exceeds the first threshold. Wireless energy receiving device according to one of Claims 1 to 3 wherein the position detecting circuit determines that alignment between the power transmitting coil and the power receiving coil is not properly performed until the circuit characteristic detected by the detecting circuit does not exceed the second threshold during a period from when the circuit characteristic value exceeds the first threshold until, when the mobile body is moved a predetermined distance. Wireless energy receiving device according to one of Claims 1 to 5 , further comprising a power reception side alarm informing a user or an external device of information, the power reception side alarm notifying the user or the external device of a detection result of the position detection circuit and the transmittable energy calculated by the position detection circuit. Wireless energy receiving device according to one of Claims 1 to 6 , further comprising a circuit that switches a connection state between the output end of the rectifier circuit and the load, wherein the circuit opens the output end of the rectifier circuit during processing by the position detection circuit. Wireless energy receiving device according to one of Claims 1 to 6 wherein the power receiving circuit further comprises a load resistor having a fixed resistance and a switching circuit that switches a connection state between the output end of the rectifier circuit and the load or the load resistor, the circuit connecting the output end of the rectifier circuit to the load resistor during processing by the position detection circuit. A wireless power transmission system that wirelessly transmits power from a wireless power transmission device to a wireless power receiving device, the wireless power transmission device comprising: a power conversion circuit that converts an input DC power to an AC power; a power transfer coil that ac the current supplied by the power converter circuit receives to generate an AC magnetic field; and a control circuit that controls the AC power to be supplied to the power transmission coil, and wherein the wireless power reception device comprises: a power receiving circuit including a power receiving coil that accepts AC power through a magnetic field, and a rectifier circuit that converts the AC power picked up from the power receiving coil to DC power and DC output to a load; a detection circuit that detects a circuit characteristic of the power receiving circuit having a first peak having a relatively large peak and a second peak having a relatively small value with respect to a horizontal separation distance between a power transmission coil of the wireless power transmission device and the power receiving coil; and a position detecting circuit that detects a state of the relative position between the power receiving coil and the power transmitting coil, the position detecting circuit determining that the power receiving coil is located near the periphery of a position suitable for receiving power from the power transmitting coil when the circuit characteristic of FIG the detection circuit detects, exceeds a first threshold set between the peak value of the second peak and a detection threshold of the detection circuit, and the position detection circuit calculates an energy transmittable by the wireless energy transmission device based on the circuit characteristic detected by the detection circuit when detected by the detection circuit circuit characteristic exceeds a second threshold, which is between the peak value of the second peak and the peak value of the first peak is estellt. Wireless power transmission system after Claim 9 wherein the control circuit controls the alternating current to be supplied to the power transmission coil such that the amount of magnetic flux generated by the energy transmission coil is constantly controlled. A wireless power transmission system that wirelessly transmits power from a wireless power transmission device to a wireless power reception device, the wireless power transmission device comprising: a power converter circuit that converts an input DC power to an AC power; a power transmission coil receiving the alternating current supplied from the power conversion circuit to generate an alternating current magnetic field; and a control circuit that controls the AC power to be supplied to the power transmission coil, and wherein the wireless power receiving device comprises: a power receiving circuit comprising a power receiving coil receiving alternating current through the alternating current magnetic field and a rectifier circuit that converts the alternating current received by the power receiving coil into direct current and outputs the direct current to a load; and a detection circuit that detects a circuit characteristic of the power receiving circuit having a first peak having a relatively large peak and a second peak having a relatively small value with respect to a horizontal separation distance between the power transmission coil of the wireless power transmission device and the power reception coil the control circuit, determines that the power receiving coil is near the periphery of a position suitable for receiving energy from the power transmission coil when the circuit characteristic detected by the detection circuit exceeds a first threshold set between the peak of the second peak and a detection threshold of the detection circuit is and calculates an energy transferable from the wireless power transmission device to the wireless power receiving device based on the circuit characteristic detected by the detection circuit when the circuit characteristic detected by the detection circuit exceeds a second threshold that is between the peak of the second peak and the peak of the first peak.

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